Carences en cobalamine : aspects neurologiques chez 27 patients

Cobalamin deficiency, hyperhomocysteinemia, and dementia

“…Hyperhomocysteinemic individuals with certain butyrylcholinesterase-K (BuChE-K) alleles cognitively decline more rapidly than those with wild-type BuChE alleles 90. Nutritional determinants include decreased vitamin B12 ingestion9,45,47 and food-cobalamin malabsorption 9,15,19,45,49,91–93…”

“…Psychiatric manifestations consist of psychoses, including paranoia, delusions, and hallucinations,23,58,179–184 cognitive dysfunction, including memory impairment, delirium, and dementia,7,21,23,49,58,93,180,181,185–188 and affective syndromes, including mania and depression,7,21,23,58,93,180,181,186,189–191 which also occurs with elevated Hcy192–194 and low SAM 67,192. Associations exist between HHcy and cognitive dysfunction in bipolar disorder195–197 and perhaps schizophrenia 198.…”

“…SCD refers to myelopathy affecting posterior and lateral columns, characterized by a pernicious sequence of vacuolar demyelination, axonal degeneration, and neuronal death 18,58,200–202. Posterior column myelopathy affects afferent pathways, causing the most common neurological signs: ataxia, diminished proprioception and vibratory senses, and presence of Romberg’s sign 18,49,58,180,185,188,200,201,203. Lateral column myelopathy affects efferent pathways, causing the second most common neurological signs: extremity muscular weakness, spasticity, hyperactive reflexes, and Babinski’s sign 18,49,58,180,181,200,201.…”

“…Peripheral and autonomic neuropathies cause hypoactive reflexes, sensory loss, orthostatic hypotension, fecal and urinary incontinence, and impotence. 18,23,49,58,92,180,181,185,188,200,203 Although optic neuropathy is uncommon,23,58,180,203 visual impairment may occasionally be the earliest or sole manifestation of the disease 203. Gastrointestinal manifestations include epithelial atrophy of the tongue, referred to as atrophic glossitis, which causes the tongue to be sore and beefy red,18,23 and epithelial atrophy of the stomach 15…”

“…Although PA, or type A chronic atrophic gastritis,181,429 is often cited as the most common cause of low serum B12,7,18,19,33,49,56,58,180,201,390 emerging evidence suggests dissociation between PA and B12-deficient dementia 10,13,15,17–19,21,30,32,33,45,47–49,56,58,91–93,146,180,190,200,201,203,290,350,368,371,373,376,393,427–434. Thus, B12-deficient dementia may be subdivided into B12-deficient dementia with PA and B12-deficient dementia without PA. Studies support the postulate that these two disease states are different 10,13–15,17,19,21,25,30,32,33,45,47–49,58,91–93,146,190,201,203,289,290,350,368,427,429,431–435.…”